Dimensionally stable anode construction

ABSTRACT

Describes dimensionally stable anodes made of a valve metal (titanium) for electrolytic cells, for the electrolysis of brine solutions and other electrolytes, having lead-in conductors of high conductivity (copper) and inverted U-shaped distributor conductors of valve metal (titanium) extending substantially the length of the anode working face in one direction and of sufficient width and being equally distributed along the anode working face in the other direction to distribute current uniformly over the anode working face, the anode working face being made of valve metal and covered with an electrocatalytic coating capable of catalyzing halogen ion discharge without becoming passivated over long periods of time.

United States Patent 1191 Loftfield et a1.

[ DIMENSIONALLY STABLE ANODE CONSTRUCTION [75] Inventors: Richard E.Loftfield, Chardon;

Ramesh C. Jhaveri, Mayfield Heights, both of Ohio [73] Assignee:Electronor Corporation, Panama City, Panama [22] Filed: Oct. 2, 1972[21] Appl. No.: 294,241

Related us. Application Data [63] Continuation of Ser. No. 880,797, Nov.28, 1969,

Primary Examiner-F. C. Edmundson Attorney, Agent, or FirmHammond &Littell 5 7 ABSTRACT Describes dimensionally stable anodes made of avalve metal (titanium) for electrolytic cells, for the electrolysis ofbrine solutions and other electrolytes, having lead-in conductors ofhigh conductivity (copper) and inverted U-shaped distributor conductorsof valve metal (titanium) extending substantially the length of theanode working face in one direction and of sufficient width and beingequally distributed along the anode working face in the other directionto distribute current uniformly over the anode working face, the anodeworking face being made of valve metal and covered with anelectrocatalytic coating capable of catalyzing halogen ion dischargewithout becoming passivated over long periods of time.

16 Claims, 8 Drawing Figures PATENTED SE8 1 (H974 sum 10F 1 INVENTORSRICHARD E. LOFTFIELD BYRAMESH c. JHAVERI 7 ATTORNEYS PATEHTEL SEE I01974 saw a or 2 INVENTORS RICHARD E. LOFTFIELD BY RAMESH C. HAYERI v,,1 A ATTORNEYS DIMENSIONALLY STABLE ANODE CONSTRUCTION This is acontinuation of Ser. No. 880,797, filed Nov. 28, 1969, now abandoned.

This invention relates to a new and improved construction ofdimensionally stable anodes for use in the electrolysis of alkali metalchlorides and other salt solutions or fused salts, which undergodecomposition under electrolysis conditions.

Dimensionally stable anodes are constructed of metals which areresistant to electrolytic cell conditions, such as valve metals, andhave negligible wear and, hence, constant stability of the workingsurface under normal cell operating conditions. They are used in placeof the graphite anodes commonly used in mercury and other electrolysiscells.

The dimensionally stable anodes of this invention will be described, byway of example, for use in the production of chlorine and sodiumhydroxide in a flowing mercury cathode electrolysis cell. They can beused in other electrolysis cells and for other purposes.

The dimensionally stable anodes of this invention are preferablyconstructed of a titanium framework and the titanium anode face isprovided with a conductive electrocatalytic coating which protects thetitanium anode face from developing a passivating film and continues toconduct electrolysis current from the face of the anode to theelectrolyte and to catalyze choride, or other halogen ion, discharge atthe anode face over long periods of time. While titanium is preferredfor the construction of our anode, other valve metals, such as tantalum,zirconium or alloys thereof may be used.

The conductive electrocatalytic coating on the face of the anode ispreferably composed of a major portion of titanium dioxide (TiO ortantalum pentoxide (Ta O together with a minor portion of an oxide of aplatinum group metal capable of rendering the titanium dioxidesemiconductive and of catalyzing chloride ion discharge at the face ofthe anode. Other electrocatalytic active coatings, such aselectro-deposited or chemi-deposited platinum group metal coatings, maybe used, but are not as desirable as the oxide coatings because of costsand unfavorable wear characteristics.

The anode face is preferably foraminate to minimize the bubble effect ofthe gas bubbles released at the anode face and avoid gas blanketing ofthe anode face.

One of the objects of the invention is to provide a dimensionally stableanode which will be economical in the use of the metal of construction,such as titanium, which is relatively expensive.

Another object of the invention is to provide a dimensionally stableanode which will give uniform current distribution from the anodelead-ins to the anode face.

Another object of the invention is to provide an anode having a lowvoltage drop from the anode lead-in to the anode face.

Another object of our invention is to provide a dimensionally stableanode with means for uniform distribution of current to the working faceof the anode, which means will not interfere with the release of gasbubbles from the working face of the anode.

Another object is to provide an anode frame which is easy to constructfrom valve metals.

Other objects and advantages of the invention will appear as thisdescription proceeds.

Referring now to the drawings, which illustrate preferred embodiments ofthe anodes of this invention:

FIG. 1 is a cross sectional view of a mercury electrolytic cell equippedwith a flexible cell cover and dimensionally stable anodes of thepresent invention;

FIG. 2 is a plan view of one embodiment of the anode;

FIG. 3 is a sectional view along the line 3 3 of FIG.

FIG. 4 is a sectional view along the line 4 4 of FIG.

FIG. 5 is a plan view of another embodiment;

FIG. 6 is a sectional view along the line 6 6 of FIG. 5;

FIG. 7 is a sectional view along the line 7 7 of FIG. 5; and

FIG. 8 is a sectional view of another embodiment.

In the embodiment of the invention illustrated in FIG. 1, anelectrolytic cell 10, of the type shown in US. Pat. No. 2,958,635 or No.3,042,602, comprises a continuously flowing mercury cathode which flowsover the cell base 11 beneath anodes l2 immersed in a brine solution,such as sodium chloride. The approximate brine level is indicated by theline A A. However, the brine level may be anywhere between the top oftheanodes and the bottom of the cell cover, if a gas release space isprovided. Electric current is supplied to the anodes and a returnconductor connected to the cathode cell base sets up a potentialdifference across the gap between the anode and cathode which causes thechloride ions to migrate to the anode, and the sodium ions to migrate tothe flowing mercury cathode, where the resultant sodium forms an amalgamwhich is conveyed out of the cell to a denuder (not shown). The chlorinegas, in bubbles, rises from the mesh openings in the face of anodes 12to an outlet passage from the cell cover, from which it flows to thechlorine recovery system.

The cell 10 is mounted between a pair of I-beams l3 and is inclined tocause the mercury to flow, by gravity, over the cell base 11. The cellcomprises a bottom wall 14 and a pair of upstanding side walls 15, madeof concrete, steel or other suitable rigid material. The side walls 15are lined with a corrosi resistant insulating material 16, such asnatural stone, or a coating of resin. The electrically conductive base11, made of steel or the like, defines the inner bottom face of thecell. A conductor arrangement 17 secured to the undersurface of thebottom wall 14 includes spaced,-upwardly projecting conductors (notshown) which contact the metal base 11, a conventional bus bar isconnected to the conductor 17 to permit completion of the circuit.Conductors 17 form the negative connections to the circuit.

A plurality of spaced, transversely disposed pillars l8 span the cellabove the I-beams l3 and are mounted on adjustable posts 19 which reston and are releasably secured to the beams 13. The pillars 18 support apair of longitudinally extending l-beams 20 on which is mounted anoverlying elongated plate 21. Spaced along the plate 21 are suitablehook members 22 which are engaged by a conventional hoisting assembly(not shown) to remove the mounting structure overlying the cell whenaccess to the interior, for repairs, is necessary.

A plurality of transversely extending anode supports 23 are secured tothe bottom face of the I-beams 20 in a conventional manner, such aswelding, and are used to support the anode structure in the cell. Aplurality of downwardly projecting lead-in conductors 24, made of copperor other highly conductive metal, are spaced along the anode supports 23and releasably secured to the latter in a conventional manner, as, forexample, by threadednuts 24a on the conductor on either side of thesupports. Bus bar connections 25, secured to a positive electric powersource (not shown) convey current to the bus bars 26 which extendtransversely of the cell and are secured to the lead-in conductors 24. Aflexible cover member 27, such as is disclosed in the aforementioned US.Pat. No. 2,958,635, overlies the cell and is secured along itslongitudinal edges to the top of the lbeam walls 13. The cover includesspaced apertures which are aligned with and receive the downwardlyprojecting lead-in conductors 24 which are sealed to the cover 27 bynuts 28. The flexible cover permits limited adjustment of the anodeswithout removal of the cover. A rigid cover may, however, be used. Allof this construction is more fully described in U.S. Pat. No. 2,958,635and No. 3,042,602.

The anode assembly constituting the subject matter of this inventioncomprises a working face 30, comprising a titanium or tantalum mesh basecovered with a conductor coating, such as a major portion of titaniumdioxide (TiO or tantalum pentoxide (Ta O together with a minor amount ofa platinum group metal oxide, capable of rendering the titanium dioxideconductive and of catalyzing chloride ion discharge at the face of theanode. Other electrocatalytically active coatings, such aselectro-deposited or chemi-deposited platinum group metal coatings maybe used. The term mesh" is intended to include thin sheets of titaniumor tantalum or of alloys of titanium or tantalum in foraminous orexpanded form, wire screen, wire mesh and gauge, rolled wire mesh,punched and slotted sheet titanium or tantalum metal or alloys oftitanium or tantalum.

The working faces 30 are connected by welding, riveting or otherconnections to a plurality of inverted U- shaped titanium conductingbars or channel bars 31, which are connected to the copper lead-inconductors 24 by means of internally screw threaded titanium bosses 32,welded or otherwise secured to the inverted U-shaped conductor bars 31.

The inverted U-shaped conductor bars 31 extend substantially from end toend of the anode working face 30 in one direction and are of such awidth and are so spaced laterally along the anode face in the otherdirection, as to convey current substantially uniformly to the anodeface. In the embodiments illustrated, two inverted U-shaped conductorbars 31 are shown but a larger or smaller number may be used dependingon the width of the anode and the number of anode leadins used. The endsof the conductor bars 31 are open.

In the embodiment illustrated in FIG. 2, the distances a, b, c and d areequal so that there is a uniform distribution of current to the half ofthe anode served by the right hand conductor bar 31. The same is true ofthe left half of the anode shown in FIG. 2. Where a single U-shapedconductor bar is used to distribute current to an anode face, it shouldbe of such width and so lo cated on the anode face as to distributecurrent uniformly to the anode face. Thus, a single wide U-shapedconductor bar 31 located at the center of the anode face, with legs 33spaced one-half the lateral distance from the center to the edge of theanode will also distribute current uniformly over the anode face. Anynumber of conductor bars 31 may be used according to this principle todistribute current uniformly to the anode face; the lead-in conductors24 being sufficient in number and spaced so as to provide uniformdistribution of current longitudinally of the anode face.

The legs 33 of the inverted U-shaped conductor bars are preferablyintegral with the conductor bars and are bent outwardly, as shown inFIGS. 1 and 3, and welded or otherwise secured to the anode face 30. Aplurality of holes 34 spaced along the inverted U-shaped conductor bars31 permit the escape of gas bubbles, released beneath the invertedU-shaped conductor bars, into the electrolyte above the anodes and outof the cell into the gas recovery system. Notches 35 in legs 33 relievestrains and permit adjustment of the working face of the anode forlevelling purposes. The U-shaped conductor bars may be made of heavygauge foraminous metal, if desired.

Cross bars 36 of L-shape connect the conductor bars 31 adjacent the endsof the conductor bars and are preferably welded to the conductor bars,as illustrated in FIGS. 2 and 4, to give greater rigidity to the anode.The lead-in conductors 24 are screw threaded into the bosses 32 so thatthe base of the lead-in conductors 24 make firm contact with the top ofthe inverted U shaped conductor bars 31 to improve the conductivity atthis point. The portion of the copper lead-in conductors 24 inside thecell 10 is protected from the corrosive effect of the electrolyte andthe cell gases by titanium sleeves 37 which are either welded to thebosses 32, as illustrated in FIG. 6, or separate from the bosses andinserted in a groove 39 (FIG. 3) in the top of the boss, any gap beingsealed by an O-ring 38. As illustrated in FIG. 3, the sleeves 37 aremade separate from the bosses 32 so that the anode may be manufacturedand shipped separately from the sleeves 37 and sleeves 37 of differentheight may be used when mounting the anodes in cells of differentheight. When the sleeves 37 are separate from the bosses 32, a fluidtight seal is formed by the O-ring 38 of neoprene or similar material.

The sleeves 37 are provided with a flanged top 37a which makes a fluidtight seal with the cell cover 27 when the anodes are assembled in acell. The flanges 37a rest against a gasket 40 which is sealed againstthe cell cover 27 by an upper gasket 41a, washer 41b and nut 28 screwedon the lead-in conductor 24. The sleeves 37 are of larger diameter thanthe lead-in conductors 24 and are spaced from the lead-in conductors. asshown in FIG. 3.

In the embodiment illustrated in FIGS. 5, 6 and 7, the inverted U-shapedconductor bars 31 are similar to the corresponding conductor barsillustrated in FIGS. 1 to 4, but the legs 330 are not bent outwardly attheir base and are welded directly to the foraminous anode face 30. Thetitanium protector sleeves 37 are welded to the bosses 33 and the upperend of the sleeves 37 are connected by connecting bars 42 welded orotherwise secured to the top of flanges 37a of sleeves 37. Cross bars360 (FIG. 7) of L-shape are welded to the anode working face 30 at eachend of the inverted U-shaped conductor bars 31. The connecting bars 42at the top of the sleeves and the cross bars 36a give the anodeillustrated in FIG. 5 a high degree of rigidity.

FIG. 8 illustrates a modification of the inverted U- shaped conductorbars 31, in which the legs 43 are bars welded to a flat conductor bar31a, carrying bosses 32, and to the anode working face 30. Thisconstruction has a higher internal resistance loss because of the largernumber of welds and, hence, is a less preferred embodiment.

The anode working faces 30 are preferably foraminous titanium mesh whichis welded to the legs 33 of the inverted U-shaped conductor bars 31.However, the anode faces may be any thin sheet of titanium or tantalumin foraminous or expanded form, wire screen, rolled wire mesh, punchedor slotted sheet titanium, spaced rods or half-round forms, asillustrated, for exampl, in FIGS. 14 to 17 of US, Pat. No. 3,308,043.

The anode illustrated is economical in the use of the metal ofconstruction such as titanium. It uses about percent less metal thanprior titanium anodes such as illustrated in U.S. Pat. No. 3,297,561,with better and more uniform distribution of current to the anodeworking face. The cross sectional area of the various parts isproportioned to the total current to be conducted to the anode workingface, so that there is no waste of the metal of construction.

Before or after the anode has been assembled as described, the front,and optionally the back, of the working face 30 is given a conductingcoating capable of conducting electrolysis current to the electrolyteand catalyzing chloride ion discharge at the working face over longperiods of time. The coating may surround the mesh strands of theworking face 30. Any suitable coating which will continue to conductcurrent to the electrolyte without becoming passivated and catalyzechloride ion discharge without high overvoltage may be used, such aselectro-deposited or chemi-deposited coatings of platinum group metals(i.e., platinum, ruthenium, iridium, rhodium, etc.) or mixture thereof,or mixed oxides of platinum group metals and film forming metals.

One such coating may be provided as follows:

EXAMPLE I Ruthenium as RuCl;.H O 10 mg (metal) Iridium as (NH ),IrCl 10mg (metal) Titanium as TiCl 56 mg (metal) Formamide (NCONHQ 10 to 12drops Hydrogen peroxide (H 0, 30%) 3 to 4 drops per 50 squarecentimeters of anode face.

The coating is prepared by first blending or mixing the ruthenium andiridium salts containing the required amount of Ru and Ir in a 2 molarsolution of hydrochloric acid (5 ml are sufficient for the aboveamounts) and allowing the mixture to dry at a temperature not higherthan 50 C until a dry precipitate is formed. Formamide is then added tothe dry salt mixture at about 40 C to dissolve the mixture. The titaniumchloride, TiCl dissolved in hydrochloric acid (15 percent strengthcommercial solution), is added to the dissolved Ru-lr salt mixture and aquantity of hydrogen peroxide (30% H 0 about 16-22 milliliters) isadded, sufficient to make the solution turn from the blue color of thecommercial solution of TiCl to a brown-reddish color.

The coating mixture, thus prepared, is applied to both sides of thecleaned titanium anode face and to the sides of the interstices in themesh, by brush, roller or the like, in multiple subsequent layers sothat the coating surrounds the mesh. After applying each layer,

the anode face is heated in an oven under forced air circulation at atemperature between 300 and 350 C for 10 to 15 minutes, followed by fastnatural cooling in air between each of the layers, and after the lastlayer is applied the anode is heated at 450 C for 1 hour under forcedair circulation and then cooled. This provides a ceramic typesemi-conducting coating on the anode face.

The amounts of the three metals in the coating correspond to the weightratios of 13.15 Ir, 13.15 Ru and 73.7 Ti and the amount of noble metalin the coating corresponds to 0.2 mg Ir and 0.2 mg Ru per squarecentimeter of projected electrode area. In place of ruthenium, anyplatinum group metal may be used and in place of titanium, tantalum oralloys thereof, other valve metals and alloys may be used in the aboveformulation. If a platinum group metal coating is used on the mesh face,it may be applied by electrodeposition or by chemi-deposition eitherbefore or after the anode working face 30 is secured on the invertedU-shaped conductor bars 31.

The holes 34 in the inverted U-shaped conductor bars 31 permit chlorinebubbles or other gas bubbles formed in the electrolysis process toescape freely from the working face of the anodes and prevent gasblanketing.

OPERATION In operation, current is supplied via the lead-in conductors24 from the electric power source connected to the bus bar 25. Equalamounts of current are distributed to the lead-in conductors 24 whichpass the same to each of the inverted U-shaped conductor bars 31. Thecurrent then flows along the inverted U-shaped conductor barsbidirectionally, i.e., current flows equally in both directions, alongthe conductor bars 31 and thus longitudinally of the anode working face30. The current is then redispersed laterally by the legs 33 of theU-shaped conductor bars along the working face 30 secured to the legs ofthe bars 31. The conductor bars 31 are symmetrically spaced withreference to the anode working face so that there is equal distributionover the entire working face of the anode. Consequently, a uniformpotential difference across the entire electrode gap is secured so thatas the brine solution passes through the gap between the anode andcathode, the electrolytic process is performed uniformly throughout theentire length and width of the gap and chlorine bubbles flow upwardlythrough the mesh of the anode working face and also through the holes 34in the inverted U-shpaed conductor bars to the outlet passage providedin the cell cover for the collection of chlorine. The anode thus impartsa uniform potential difference over the entire electrode gap to maximizethe liberation of chlorine or other products of the electrolysisprocess.

The use of massive perforated titanium conductor bars 31, in preferenceto mesh conductor bars 31, provides better conduction to the mesh anodeworking face, which is less electrically efficient, as a conductor,

but because of the mesh configuration permits discharge of the chlorinebubbles from the anode working face and substantially eliminates gasblanketing of the anode working face.

The words titanium and tantalum are intended to include also alloys ofthese metals and the word weldingis intended to include other equivalentmethods of connecting metal parts such as riveting, screw threading theparts together, etc.

It will be evident to those ordinarily skilled in the art that variousmodifications and changes may be made from the embodiments shown withoutdeparting from the principles of this invention.

We claim:

1. A dimensionally stable anode for use in a flowing mercury cathodeelectrolysis cell comprising a planar mesh anode made of a valve metalprovided with an electrically conductive, electrocatalytic coating onthe working anode face, at least one laterally inverted, U- shapedconducting bar open at both ends connected by the integral legs of thebar to the mesh anode and extending substantially from end to end of theworking face, the legs of the conductor bar being equally spacedlaterally along the anode face in the other direction so the distancebetween the center line and each leg is equal and the distance betweenlaterally parallel bars is twice the distance between the center lineand each leg to provide uniform longitudinal distribution of current onthe anode face, and means on said conductor bar for a detachableconnection to electrical lead-ins.

2. The anode of claim 1, in which the inverted U- shaped conducting barsare of massive titanium and have gas escape holes therein and the anodeis made of titanium.

3. The anode of claim 1, in which lead-in conductors are connected tothe conductor bar and liquid and gasproof sleeves surround and arespaced from the lead-in conductors inside the cell and extend betweenthe inverted U-shaped conducting bars and the cell cover.

4. The anode of claim 3, in which the inverted U- shape conducting barsand the anode working face are titanium.

S. The anode of claim 2, in which the anode working face has asemi-conducting coating thereon.

6. The anode of claim 3, in which the sleeves are titanium and areseparate from the inverted U-shaped conducting bars and have a flangemaking a liquid and gasproof seal with the cell cover and a base makinga liquid proof seal with the inverted U-shaped conducting bars.

7. The anode of claim 4, in which the inverted U- shaped conducting barshave bosses thereon for securing the lead-in conductors thereto andholes for the escape of gas bubbles released beneath the inverted U-shaped conductor bars.

8. The anode of claim I, in which the legs of the inverted U-shapedconducting bars are flanged and the flanges are notched to permitrelative movement of one part of the flange relative to the other forlevelling adjustment.

9. The anode of claim 7, in which internally threaded titanium bossesare secured to the inverted U-shaped conducting bars for detachableconnection with electrical lead in conductors.

10. An anode assembly for electrolytic cells which comprises a titaniumsleeve having a flat titanium closure attached in fluid-tight manneracross one end, a current lead-in rod at least partially within thesleeve and coaxial therewith having one end in contact with the titaniumclosure, and a foraminate titanium structure carrying on at least a partof its surface a coating comprising an operative electrode material, thesaid foraminate titanium structure lying in a plane parallel to the saidtitanium closure and being electrically connected thereby by titaniummembers which, together with the said closure, define an invertedchannel shape.

11. An anode assembly according to claim 10, wherein the said titaniummembers and the titanium closure which together define an invertedchannel shape have been fabricated from one integral piece of titaniummetal.

12. An anode assembly according to claim 10, wherein the edges of thetitanium channel shape are welded at intervals to the foraminatetitanium structure.

13. An anode assembly according to claim 10, wherein the operativeelectrode material is selected from the group consisting of platinumgroup metals and oxides thereof.

14. An anode assembly according to claim 10, wherein the coatingcomprising an operative material consists of at least one oxide of atleast one platinum group metal as the operative electrode material andtitanium dioxide.

15. An anode assembly according to claim 14, wherein the said operativeelectrode material is ruthenium dioxide.

16. An anode assembly for electrolytic cells comprising:

a downwardly-facing, open-ended, horizontallyelongated titanium channelmember having a web portion and two depending flange portions integralwith the web portion:

a titanium sleeve secured at one end to said web portion in afluid-tight manner so that said web portion closes said end, said webportion having at least one gas escape opening therethrough locatedintermediate said tube and each end of said channel:

a current lead-in rod of smaller diameter than said sleeve at leastpartially within said sleeve coaxially therewith having one end incontact with said web portion: and

a foraminate titanium structure lying in a plane parallel to said webportion and electrically connected to the lower edges of the flangeportions, said foraminate structure carrying on at least a part of itssurface a coating comprising an operative electrode material.

1. A DIMENSIONALLY STABLE ANODE FOR USE IN A FLOWING MERCURY CATHODEELECTROLYSIS CELL COMPRISING A PLANAR MESH ANODE MADE OF A VALVE METALPROVIDED WITH AN ELECTRICALLY CONDUCTIVE, ELECTROCATALYTIC COATING ONTHE WORKING ANODE FACE, AT LEAST ONE LATERALLY INVERTED, U-SHAPEDCONDUCTING BAR OPEN AT BOTH ENDS CONNECTED BY THE INTEGRAL LEGS OF THEBAR TO THE MESH ANODE AND EXTENDING SUBSTANTIALLY FROM END TO END OF THEWORKING FACE, THE LEGS OF THE CONDUCTOR BAR BEING EQUALLY SPACEDLATERALLY ALONG THE ANODE FACE IN THE OTHER DIRECTION SO THE DISTANCEBETWEEN THE CENTER LINE AND EACH LEG IS EQUAL AND THE DISTANCE BETWEENTHE LATERALLY PARALLEL BARS IS TWICE THE DISTANCE BETWEEN THE CENTERLINE AND EACH LEG TO PROVIDE UNIFORM LONGITUDINAL DISTRIBUTION OFCURRENT ON THE ANODE FACE, AND MEANS ON SAID CONDUCTOR BAR FOR ADETACHABLE CONNECTION TO ELECTRICAL LEAD-INS.
 2. The anode of claim 1,in which the inverted U-shaped conducting bars are of massive titaniumand have gas escape holes therein and the anode is made of titanium. 3.The anode of claim 1, in which lead-in conductors are connected to theconductor bar and liquid and gas-proof sleeves surround and are spacedfrom the lead-in conductors inside the cell and extend between theinverted U-shaped conducting bars and the cell cover.
 4. The anode ofclaim 3, in which the inverted U-shape conducting bars and the anodeworking face are titanium.
 5. The anode of claim 2, in which the anodeworking face has a semi-conducting coating thereon.
 6. The anode ofclaim 3, in which the sleeves are titanium and are separate from theinverted U-shaped conducting bars and have a flange making a liquid andgas-proof seal with the cell cover and a base making a liquid proof sealwith the inverted U-shaped conducting bars.
 7. The anode of claim 4, inwhich the inverted U-shaped conducting bars have bosses thereon forsecuring the lead-in conductors thereto and holes for the escape of gasbubbles released beneath the inverted U-shaped conductor bars.
 8. Theanode of claim 1, in which the legs of the inverted U-shaped conductingbars are flanged and the flanges are notched to permit relative movementof one part of the flange relative to the other for levellingadjustment.
 9. The anode of claim 7, in which internally threadedtitanium bosses are secured to the inverted U-shaped conducting bars fordetachable connection with electrical lead in conductors.
 10. An anodeassembly for electrolytic cells which comprises a titanium sleeve havinga flat titanium closure attached in fluid-tight manner across one end, acurrent lead-in rod at least partially within the sleeve and coaxialtherewith having one end in contact with the titanium closure, and aforaminate titanium structure carrying on at least a part of its surfacea coating comprising an operative electrode material, the saidforaminate titanium structure lying in a plane parallel to the saidtitanium closure and being electrically connected thereby by titaniummembers which, together with the said closure, define an invertedchannel shape.
 11. An anode assembly according to claim 10, wherein thesaid titanium members and the titanium closure which together define aninverted channel shape have been fabricated from one integral piece oftitanium metal.
 12. An anode assembly according to claim 10, wherein theedges of the titanium channel shape are welded at intervals to theforaminate titanium structure.
 13. An anode assembly according to claim10, wherein the operative electrode material is selected from the groupconsisting of platinum group metals and oxides thereof.
 14. An anodeassembly according to claim 10, wherein the coating comprising anoperative material consists of at least one oxide of at least oneplatinum group metal as the operative electrode material and titaniumdioxide.
 15. An anode assembly according to claim 14, wherein the saidoperative electrode material is ruthenium dioxide.
 16. An anode assemblyfor electrolytic cells comprising: a downwardly-facing, open-ended,horizontally-elongated titanium channel member having a web portion andtwo depending flange portions integral with the web portion: a titaniumsleeve secured at one end to said web portion in a fluid-tight manner sothat said web portion closes said end, said web portion having at leastone gas escape opening therethrough located intermediate said tube andeach end of said channel: a current lead-in rod of smaller diameter thansaid sleeve at least partially within said sleeve coaxially therewithhaving one end in contact with said web portion: and a foraminatetitanium structure lying in a plane parallel to said web portion andelectrically connected to the lower edges of the flange portions, saidforaminate structure carrying on at least a part of its surface acoating comprising an operative electrode material.